id	summary	reporter	owner	description	type	status	component	version	severity	resolution	keywords	cc	stage	has_patch	needs_docs	needs_tests	needs_better_patch	easy	ui_ux
31389	Django SQLite3 ExtractWeek returns week one instead of the last week of the year.	Daniel Mössner	nobody	"I'm using: SQLite3 and Django 3.03

I've got the following query:
{{{
self.changes
            .annotate(week=ExtractWeek('date'),
                      year=ExtractYear('date'))
            .values('year', 'week')
            .annotate(balance=Avg('balance'))
            .values('year', 'week', 'balance', 'date')
            .order_by('year', 'week')
}}}


The Change model looks like this:
{{{
class Change(models.Model):
    account = models.ForeignKey(Account, on_delete=models.CASCADE, related_name=""changes"")
    date = models.DateTimeField()
    category = models.ForeignKey(Category, related_name=""changes"", null=True,
                                 on_delete=models.SET_NULL)
    description = models.TextField(blank=True)
    change = models.DecimalField(decimal_places=2, max_digits=15)
    # query optimization
    balance = models.DecimalField(max_digits=15, decimal_places=2, null=True, blank=True)
}}}


I've got a change with the following date:
{{{
datetime.datetime(2019, 12, 30, 15, 12, tzinfo=<UTC>)
}}}
Now the query turns this date into:
{{{
{'week': 1, 'year': 2019, 'balance': Decimal('7488.74000000000')}
}}}
That makes no sense, as the week should be 52 or 53.


I tried the following:
{{{
select *, strftime('%W', date) from banking_change where id=2742 limit 1;
returns week: 52
}}}

{{{
datetime(2019, 12, 30, 15, 12, tzinfo=pytz.utc).strftime('%W')
returns week: 52
}}}

It doesn't matter if the datetime is localized to Europe/Berlin before.


Why does django say that the week is 1? Seems like a bug to me.
"	Bug	closed	Database layer (models, ORM)	3.0	Normal	invalid	sqlite3 extraxweek query		Unreviewed	0	0	0	0	0	0